Modified Design of a Precision Planter For a Robotic Assistant Farmer

1-2-2- Depth Control system 
Farm equipment engineers usually use two types of mechanisms to control the depth of 
the furrow; parallelogram system and trailing arm system. Parallelogram system, is more 
accurate, easier to control and more rigid with higher strength, but is more complex and 
expensive, needs more space and it is heavier. On the other hand, trialing arm system is simpler, 
cheaper and lighter but it does not provide enough accuracy in depth control and down force 
control. Seeder mechanism in Figure 1-2 is an example of trailing arm system and Figure 1-5 
shows a parallelogram mechanism.

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The seeding mechanisms which utilize a disc opener usually use a gauge wheel and is 
very accurate in depth control. The gauge wheel is usually installed on the side of the disc, and 
its height can be changed and set by the farmer to get the proper depth. The gauge wheel in a 
planter is shown in Figure 1-5. 
1-2-3- Seed metering system 
A planter has a precise seed metering system; this is the major difference between a 
planter and a seeder. Generally seed metering systems are categorized into two main groups, 
mass flow seed metering system and precision seed metering system. A planter utilizes a 
precision seed metering system while a seeder usually comes with a mass flow seed metering 
system. Precision seed metering systems technically are used to singularize seeds and deliver 
them at a pre-specified spacing to the soil, one by one. A mass flow seed metering system 
controls the output rate of the seed to make sure the seed is fed to the ground with the proper 
rate. Figure 1-5 shows a planter mechanism which utilizes disc coulter to dig a furrow and 
vacuum (pneumatic disc) for precision seed metering system. Other types of precision seed 
metering systems are finger type, pressure drum, mechanical plate type and belt type.